Response of the Human Urinary Bladder to Angiotensins: A Comparison between Neurogenic AND Control Bladders

Abstract The response of the human detrusor muscle to angiotensins was investigated and compared between neurogenic and control bladders. Both angiotensin I and II induced potent contraction of the human detrusor muscle. Saralasin completely inhibited the response to both angiotensins, while verapamil and indomethacin barely suppressed the contractility provoked by angiotensin II. Captopril completely blocked the response to angiotensin I. The contractile response of angiotensin II was abolished in Ca ++ -free Krebs’ solution. The contractile strength of the neurogenic bladders induced by both angiotensin I and II was significantly weaker than that of the controls. However, there was no difference in ED 50 value between the 2 groups. These results support the hypothesis that angiotensin I is converted to angiotensin II by angiotensin converting enzyme in the detrusor, and that angiotensin II subsequently contracts the detrusor muscle through angiotensin II receptors. The bladder contractility induced by the angiotensins was significantly less potent in the neurogenic bladders than in the control.